CPI 4CX20-000A

The 4CX20,000A/8990 is a power tetrode intended
for use in audio or radio frequency applications. It
features an internal mechanical structure which
results in high RF operating efficiency. Low RF
losses in this structure permit operation at full
ratings up to 110 MHz and at reduced ratings to
220 MHz. The 4CX20,000A/8990 has a gain over
18 dB in FM broadcast service, and is also recommended for radio frequency linear power amplifier
service, and for VHF-TV linear amplifier service.
The anode is rated for 20 kW of dissipation with
forced air cooling and incorporates a new highly
efficient cooler design, which significantly reduces air pressure and flow requirements and
produces low acoustical noise.
Class of Operation
Characteristics
Plate Dissipation (Max.)
Screen Dissipation (Max.)
Grid Dissipation (Max.)
Frequency for Max. rating (CW)
Amplification Factor
Filament/Cathode
Voltage
Current
Capacitance
Input
Output
Feedthrough
Capacitance
Input
Output
Feedthrough
Cooling
Base
Air Socket
Air Chimney
Boiler
Length
Diameter
Weight
Maximum Ratings
Type of Service
Plate Voltage
(Volts)
Plate
Current
(Amps)
20,000 Watts
450 Watts
200 Watts
110 MHz
6.7
Thoriated Tungsten
10.0 Volts
140 Amps
Grounded Cathode
190 pf
23.5 pf
1.5 pf
Grounded Grid
83 pf
24.5 pf
0.2 pf
Forced Air
Special, Coaxial
SK-320
SK-326
--9.5 in; 341.3 mm
8.8 in; 223.5 mm
19.2 lb; 8.75 kg
T ypical Operation
Plate
Screen
Voltage Voltage
(Volts)
(Volts)
Plate
Current
(Amps)
Drive
Output
Power Power
(Watts) (kiloWatts)
C
RF amplifier
10,000
5.0
9,000
900
4.0
26.4
28.2
C
RF amplifier at 88.3 MHz
10,000
5.0
9,000
800
4.1
325
28.75
C
RF amplifier at 107.7 MHz
10,000
5.0
9,000
800
4.2
360
28.9
The values listed above represent specified limits for the product and are subject to change. The data should be used for basic
information only. Formal, controlled specifications may be obtained from CPI for use in equipment design.
For information on this and other CPI products, visit our website at: www.cpii.com,
or contact: CPI MPP Division, Eimac Operation, 607 Hansen Way, Palo Alto, CA 94303
telephone : 1(800) 414-8823. fax : (650) 592-9988 | email : powergrid@cpii.com
CPI | 4CX20,000A/ 8990
CPI | 4CW50,000J
4CX20,000A/8990